This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C xc2xa7119 from an application entitled Method Of Restricting The Call Of A Moving Subscriber In A Switched Radio Telephone System According To International Standard Protocol IS-41C earlier filed in the Korean Industrial Property Office on Aug. 26, 1998, and there duly assigned Ser. No. 98-34663 by that Office.
1. Field of the Invention
The present invention relates to the standard protocol of IS-41C and to providing call restrictions on a moving subscriber in a radio communication system, and more particularly a method of restricting the call of a moving subscriber within a contract areas for which the moving subscriber has contracted with a radio communication service provider to receive the service.
2. Description of the Related Art
There has been developed and standardized the technology for controlling the mobility of a moving subscriber for CDMA (Code Division Multiple Access) or PCS (Personal Communication Service) starting from IS-41A of EIA/TIA (Telecommunications Industry Association/Electronic Industries Association) in the year of 1991, and IS-41C in the year of 1995 was established as the standard protocol for controlling a moving subscriber, for example, in the Korean PCS systems and the Chinese Shanghai model DCS system. Discussions of the IS-41C protocol are provided in U.S. Pat. No. 5,850,445 to Yick Man Chan et al. entitled Authentication Key Management System And Method and U.S. Pat. No. 5,915,220 to Sivananthan Chelliah entitled System And Method For Maintaining Profile Information In A Telecommunications Network, both being incorporated by reference herein.
The information on a moving subscriber defined in the standard protocol of IS41C is stored into a parameter called xe2x80x98profilexe2x80x99, where the restriction of a call is defined. FIG. 1 shows the definition for restricting a call stored in a conventional moving subscriber profile of IS-41C standard protocol. According to the definition of the parameter of the geographic authorization in the moving subscriber profile, there are shown four types of call restrictions of a moving subscriber, as follows:
1. Allowance of call for all service providers.
2. Allowance of call for one service provider.
3. Allowance of call in one system.
4. Allowance of call in one location area ID (LAI).
Presently, although each communication service provider does not provide for the function to restrict a call according to the systems or areas, such function would be necessary.
According to the above moving subscriber profile of IS-41C, the last unit of the calling range is defined based on LAI. For example, when there is defined a moving subscriber allowed to receive the services only in area xe2x80x98Axe2x80x99, a plurality of systems or LAI""s cause some problems in restricting the call. Hence, the call restriction defined as defined in the conventional moving subscriber profile of IS-41C standard protocol can not provide for proper restriction of the call. In addition, a Russian city may be provided with the services as a single cell or two cells, so that there is demanded the function to restrict the call by cell.
It is an object of the present invention to provide a method for restricting the call of a moving subscriber which may provide a call restriction by cells in addition to the four types of call restrictions defined in the parameter of the geographic authorization of the moving subscriber profile in IS-41C standard protocol.
It is another object of the present invention to provide a method for restricting the call of a moving subscriber which may change the value of the parameter of the geographic authorization to provide multiple restrictions for each restriction type.
According to the present invention, a method of restricting the call of a moving subscriber in a switched radio telephone system employing the moving subscriber profile of international standard protocol IS41C, which consists of 8 bits with modification of the upper 4 bits to represent values to restrict a moving subscriber, respectively, to a service provider, system, area and cell and the lower 4 bits to restrict the scope of the values, comprises the steps of registering the call restriction regions of a moving subscriber in a moving subscriber control register according to a given parameter of the moving subscriber profile, searching the call restriction information of the moving subscriber registered in the moving subscriber profile of the control register when receiving or sending a call, and allowing the call provided the moving subscriber agrees with the call restriction information.
The present invention will now be described more specifically with reference to the drawings attached only by way of example.